"File / Delete => Symbols..." : This will bring up the "Delete Symbol(s)" dialog with a list of the current symbols. Select symbols from the list to be deleted and click on "Ok" to delete them. If any instances of a deleted symbol type exist in the model, those entities are not deleted, but their geometry will vanish. It is advisable to delete all instances of a symbol from the model before deleting the symbol type.

"File / Delete => Patterns..." : This will bring up the "Delete Pattern(s)" dialog with a list of the current patterns. Select patterns from the list to be deleted and click on "Ok" to delete them. If any polygons in the current model are using a deleted pattern type, those polygons will revert back to a solid-fill appearance.

"File / Delete => Fonts..." : This will bring up the "Delete Font(s)" dialog with a list of the current font definitions. Select fonts from the list to be deleted and click on "Ok" to delete them. If any annotations in the current model are using a deleted font type, those annotations will revert back to using a default font.

"File / Delete => Colors..." : This will bring up the "Delete Colors(s)" dialog with a list of the current custom color definitions. Select colors from the list to be deleted and click on "Ok" to delete them. Any entities in the current model that are using the deleted color(s) are unaffected.

"File / Delete => Lights..." : This will bring up the "Delete Light(s)" dialog with a list of the current lights. Select lights from the list to be deleted and click on "Ok" to delete them. The current model will be redrawn without illumination from the deleted lights.